New SMITHS Vacuum Gauge Launched by CAI

Caerbont Automotive Instruments Ltd (CAI) has launched a new low-energy Vacuum Gauge to measure the manifold vacuum in an engine. The new gauge replaces less-reliable mechanical gauges. Vacuum Gauges are commonly used on Classic Cars to assist with tuning for power, diagnosing engine faults, and for measuring fuel economy.

The new Vacuum Gauge has been added to the successful SMITHS Auxiliary range of gauges for classic cars. This type of gauge is connected to the car’s inlet manifold to measure the Manifold Vacuum, which is the difference in air pressure between the engine's intake manifold and Earth's atmosphere.

In operation, the Vacuum Gauge measures the amount of air pressure inside the engine. Whenever the engine is running, a vacuum is created. Pressure measurements are taken at the intake manifold by the carburetor or by the throttle body if fuel is injected. The Vacuum Gauge uses a modern stress / strain gauge sender attached to the intake manifold of the engine.

Installing a Vacuum Gauge has many benefits including enabling early identification of engine vacuum leaks. These are normally difficult to diagnose as they could manifest as a crack in a hose, a loose carburetor gasket, or a leaky EGR (Exhaust Gas Re-circulation) valve. In each instance, using an automotive Vacuum Gauge will help pinpoint a specific diagnosis for the problem.

Gauges to measure the Manifold Pressure were very popular in the 1970s during the Oil Crisis and were commonly known as the ‘Econometer’ gauge. Petrol and Diesel were both in short supply with rising prices, and the gauge was used to tune the engine and maintain maximum fuel economy.

There are two variants of the new SMITHS Vacuum Gauge. The Model VG1302-03CB measures Hg (mercury), whilst the Model VG1302-04CB measures Kpa (Kilopascals). Each Vacuum Gauge is 52mm in diameter with a ½ vee Chrome bezel and clamp fixing. The face of the gauge is LED lit and styled to match other SMITHS Classic Gauges. The SMITHS Vacuum Gauge operates in conjunction with a sender unit (Model PTTR2300-03-8NKIT).